EP 1148631 A1 20011024 - Frequency translator with image frequency signal suppression
Title (en)
Frequency translator with image frequency signal suppression
Title (de)
Frequenzumsetzer mit Unterdrückung der Spiegelfrequenzen
Title (fr)
Convertisseur de fréquence avec rejet de fréquence image
Publication
Application
Priority
FR 0004996 A 20000418
Abstract (en)
The frequency converter receives an input signal (IS) having intermediate frequency (IF) and a voltage-controlled oscillator (VCO) signal (OS) having local oscillator frequency (FLO), and delivers an output signal (RS) having radio frequency (RF), which is equal to the difference of the local oscillator frequency and the intermediate frequency. The frequency converter comprises two quadratic modules (QM1,QM2) receiving the oscillator signal (OS) and the input signal (IS), respectively, and delivering the phase quadrature components (LO1,LO2) of the oscillator signal, and the phase quadrature components (FI1,FI2) of the input signal; two mixers (MX1,MX2) delivering output signals (RS1,RS2) representative of the products of the first output signals (LO1,FI1) and of the second output signals (LO2,FI2) of the quadratic modules; and the means for recombining the output signals of mixers to obtain the radio-signal for transmission. Each mixer (MX1,MX2) contains two differential pairs of transistors forming a Gilbert cell, whose conductance is controlled by one of the output signals of the first quadratic module, and which are biased by means of one of the output signals of the second quadratic module. The second quadratic module (QM2) contains a transconductance stage, which allows to transform the voltage information carried by the input signal into the current information. The second quadratic module also contains a polyphase filter, which allows to produce a set of currents, mutually phase-shifted and representative of the information carried by the input signal. The second quadratic module and the first and second mixers are incorporated within the same integrated circuit. The radio-telephone apparatus containing a signal processing unit (SPU) and an antenna (ANT) for transmitting the radio-frequency signal, also contains the frequency converter of proposed type, which receives the former a an input signal, and delivers the latter as an output signal.
Abstract (fr)
La présente invention concerne un convertisseur de fréquence, destiné délivrer un signal de sortie ayant une fréquence radio FR, égale à la différence entre la fréquence FLO d'un signal OS provenant d'un oscillateur VCO et la fréquence FI d'un signal d'entrée IS. Selon l'invention, un tel convertisseur de fréquence inclut : deux modules quadratiques QM1 et QM2 pour séparer le signal provenant de l'oscillateur OS et le signal d'entrée IS en deux composantes (LO1,LO2) et (FI1,FI2) en quadrature de phase, deux mélangeurs MX1 et MX2 pour multiplier deux-à-deux les composantes ainsi obtenues, des moyens de combinaison COMB pour recombiner les signaux de sortie RS1 et RS2 des mélangeurs MX1 et MX2. L'invention permet au convertisseur de fréquence de réaliser, de manière interne, une bonne réjection de la fréquence image, tout en offrant de bonnes performances en bruit et un gain et une linéarité améliorés par rapport aux convertisseurs connus. Application : Décalage en fréquence avant émission dans un radiotéléphone. <IMAGE>
IPC 1-7
IPC 8 full level
CPC (source: EP US)
H03C 1/542 (2013.01 - EP US)
Citation (search report)
- [X] US 5847623 A 19981208 - HADJICHRISTOS ARISTOTLE [US]
- [X] EP 0903846 A2 19990324 - ALPS ELECTRIC CO LTD [JP]
- [X] WO 9520284 A1 19950727 - PHILIPS ELECTRONICS NV [NL], et al
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 1148631 A1 20011024; EP 1148631 B1 20060920; DE 60123157 D1 20061102; DE 60123157 T2 20070830; FR 2807896 A1 20011019; JP 2001358537 A 20011226; JP 4765029 B2 20110907; US 2002008983 A1 20020124; US 6819913 B2 20041116
DOCDB simple family (application)
EP 01201332 A 20010411; DE 60123157 T 20010411; FR 0004996 A 20000418; JP 2001116798 A 20010416; US 83563401 A 20010416